Past tense processing and language breakdown:

What does ‘normal’ look like?

Jennifer Aydelott

Rob Leech

Maciej Trzaskowski

Patient Study

Past Tense Debate: distinct mechanisms for regular and irregular verbs?

goal: reconcile findings from studies of morphological processing and lexical priming in aphasia

stimuli: spoken word pairs tasks: explicit judgment, implicit priming types of linguistic information: morphology,

phonology, semantics participants: LH damage + language impairment

pattern of brain activity in healthy adults?

Proposed Design

16-20 healthy adult volunteers 3 explicit judgment tasks [yes/no button press]

morphology [past tense match?] irregular: sank-sink / sinked-sink / threw-sink regular: linked-link / lank-link / showed-link

phonology [same?] pseudo-irregular: pink-pink / pank-pink / twun-pink pseudo-regular: mink-mink / minked-mink / bunned-mink

semantics [meaning related?] relationship: nest-bird / sky-bird / vase-bird

+ baseline noise discrimination [same?]

noise pairs: white-white / pink-pink / white-pink / pink-white

Proposed Design whole brain fMRI semi-sparse sampling

(TR=5s, TE=50ms, 3x3x4mm resolution)

mixed blocked & event-related design

162 trials per task (minimum 27 trials per condition)

task blocks interspersed with baseline

trial order pseudorandomized task order counterbalanced

full factorial analysis (GLM)

block 154 trials4.5 mins

block 254 trials4.5 mins

block 354 trials4.5 mins

baseline2 mins

baseline2 mins

task 1

task 2

task 3